Water-soluble cellulose ethers have been employed in a wide variety of applications, such as, for example; in personal care applications such as pharmaceutical and cosmetic compositions; and industrial applications such as viscosity adjusters, suspension aids, oil field drilling and fracturing materials and adhesion promoters.
Cationic modification of cellulose ethers is desirable particularly when the cellulose ethers are used in personal care applications, e.g., for enhanced substantivity to skin and hair. Such cationic modification is also desirable for certain industrial applications, e.g., flocculation of fines in water treatment, binders in paper manufacture, adhesion promotion to siliceous materials, etc., all of which depend on substantive properties.
Hydrophobic modification of cellulose ethers is also desirable. It provides important properties in industrial applications. For example, in latex paint, thixotropy, rheology (reversible shear dependent viscosity) and surface activity (pigment dispersion) result from hydrophobe modified cellulose ethers. However, the amount of hydrophobe that can be incorporated is restricted when water solubility is required, viz., incorporation of hydrophobe reduces water solubility.
There exists a need for new cellulose ether derivatives which display some of the above properties, but which also are saline compatible, non-irritating, substantive to mucous membranes of the eye, nose, mouth, vagina and gastrointestinal tract, and which can be formulated with therapeutic or cosmetic ingredients for personal care applications. Such new cellulose ether derivatives may also have new industrial applications as well.